Advantages and disadvantages of supressed TSH

Hi, guys! As I read posts and posts, questions and answers, suggestions, blogs, articles, papers, experiences, etc., I can tell some think supressed TSH is good, others believe it's bad and others consider that it is not that important, and some don't even address it at all. Therefore, if you guys can help me, I would like to know what are some of its advantages and disadvantages, so I can decide what suits me best or what I should make a priority as far as my thyroid is concerned.

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11 Replies

  • I would say your symptoms. It really all depends on how you feel in yourself. Everyones different

  • Puducita,

    What should be the priority is taking the minimum dose required to relieve symptoms.  Most people on Levothyroxine will be comfortable with TSH 1.0 or lower,  FT4 in the upper quadrant, and FT3 towards/in the upper third of range.  The dose some patients need to deliver good levels of FT4 and FT3 may suppress their TSH incidentally but suppression of TSH shouldn't be the target.

    Lingering symptoms when optimally medicated on thyroid replacement are often due to low or deficient ferritin, vitamin D, B12 and folate so it can be worth having blood tests to check levels.

    Thyroidectomised thyCa patients need suppressed TSH to avoid stimulation of any stray or remnant thyroid cells which might cause recurrence of the cancer. 

    Patients with severe thyroid eye disease (TED) and patients with Hashimoto's may benefit as suppressing TSH reduces thyroid activity which can exacerbate TED and Hashimotos.

    It's commonly thought that suppressed TSH increased the risks of atrial fibrillation and osteoporosis but recent research debunks this.  Unfortunately, it takes up to 17 years on average for new research to filter down and many doctors continue to be very averse to suppressed TSH and will reduce dose even though FT4 and FT3 may not be ideal.


    I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

  • Thank you, you were very clear. One more question, are there people who feel unwell due to supressed tsh regardless of optimal t4 ad t3 levels? 

  • Puducita,

    Yes,  because their doctors tell them thyroid levels are good when they aren't, because they have Hashimoto's, or they may have vitamin and mineral deficiencies.  It's possible, of course, that they may also have other non-thyroidal illness.

    If you are talking about yourself post your thyroid results and ranges and any results and ranges for ferritin, vitamin D, B12 and folate and members will advise.

  • Hi Clutter

    Do you have a link or reference to some of the recent research you mention that debunks the belief that suppressed tsh can cause osteoporosis and atrial fibrillation? 

    My GP is obsessed with this idea and keeps trying to reduce my dosage. I'd like to give her something to read! Thanks.

  • MarsBar12,

    If you want the full text you'll have to request patient access from the Endocrine Society.

  • my tsh is 0.01 & I feel better than I ever have in 15 years.. I take thyroid s & my doctor is fine with treating my symptoms rather that tsh levels! 

  • The best I ever felt also was when my tsh was down at 0.001!! 

  • If you on t3 or ndt your TSH will be suppressed anyway its the perfectly normal response of the pituarity feedback system

  • It all depends on how you FEEL  not numbers.

  • Hi Puducita, Can't tell whether you already know this, but thought I'd mention just in case, the basics of what TSH is: 

    TSH stands for Thyroid Stimulating Hormone. It's a hormone generated by the pituitary, in order to call the thyroid to produce more thyroxine. The pituitary does this when it detects that there isn't enough thyroxine floating around in the body.

    FreeT4 and freeT3 are both measures of how much thyroxine there is available in your blood. T3 is the active hormone used by cells and tissues, and T4 is the storage form - cells and tissues convert it themselves into active form. 

    The default pattern is that as fT3 and fT4 drop, your pituitary will make more and more TSH to tell your thyroid to make more. If fT3 and fT4 are high, less TSH will be made. So in general, if you have good levels of T3 and T4, you will also have a low TSH. If there is a disconnect between this set of numbers, it means something more unusual is going on to disrupt them. 

    So a suppressed TSH means you have pretty high T3 and T4. There's a concern this means your own thyroid is getting no stimulation at all, so is doing nothing and completely relying on the medicine you are taking. This view is widely shared by GPs, but you don't hear it much round here, as I think generally people don't mind too much whether the thyroxine that allows them to be mobile and and live a good life comes from a tablet or their own gland. 

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